Fuel cells have been proposed as an alternative clean and efficient electrical power source. Particularly, fuel cells can be used to power vehicles instead of using traditional power generation methods, such as internal combustion engines. Generally, a single fuel cell cannot generate a substantial amount of power. Fuel cells are arranged in stacks to supply the needed energy requirements for a vehicle.
A proton exchange membrane fuel cell is a type of fuel cell consisting of an anode, a cathode, and an electrolyte membrane. The electrolyte membrane is disposed between the cathode and the anode. Diffusion layers may be disposed adjacent the anode and cathode for distributing reactants such as hydrogen gas and air. An electrochemical reaction within the fuel cell produces water as a reaction product. The water is absorbed by the electrolyte membrane in each fuel cell during operation, causing the overall length of the fuel cell stack to vary in some stack designs.
Electrical connections at either end of a fuel cell stack must accommodate the varying length of the fuel cell stack. This must be done while maintaining strict space requirements, keeping cost low to manufacturers, and maintaining the ability to carry high currents. Prior attempts to maintain these parameters have been accomplished by using sliding joints, flexible braided connectors, and cantilever style bus bars.
Sliding joint connectors, commonly known as fork plugs, have a blade and a fork that allow for a small amount of movement while maintaining an electrical contact between the blade and the fork. Despite a rather compact size, the sliding joint connectors have proved a restrictive option for electrical connections at the end of a fuel cell stack due to a high cost, space requirements, and limited range of movement. Accordingly, sliding joint connectors are not a suitable choice for vehicle manufacturers.
Flexible braided connectors have also failed as a practical means to meet the needs of vehicle manufacturers. The braided connectors contain air space in the braids and do not maintain the space efficiency of a solid connector. Despite a capability of allowing sufficient movement of a fuel cell stack, braided connectors have proven too expensive to be feasible, while additionally failing to fall within the stringent space requirements.
As a third option, cantilever style bus bars are an inadequate option as well. The cantilever style bus bars maintain electrical contact by a biasing force within the connector. While a cost effective option, the cantilever style bus bars require a large space to accommodate the varying length of a fuel cell stack, limiting the use thereof in vehicle applications.
It would be desirable to provide a cost effective flexible electrical connector that allows for sufficient movement between two points in an electrical system while maintaining strict space requirements.